Check valves permitting free fluid flow in one direction from the supply or inlet port to the delivery or outlet port and preventing fluid flow in a reverse direction are well known in the art. Of a particular interest is a poppet check valve that includes a moving poppet member that normally uncovers the supply port when the fluid pressure at such supply port is greater than the fluid pressure at the delivery port and covers (seals) the supply port to prevent the fluid flow in the reverse direction when the fluid pressure at such supply port is less than the fluid pressure at the delivery port. The poppet check valves may be of a self-sealing type or use a bias spring or other mechanical arrangements to bias the poppet member for covering the supply port. The self-sealing check valves are generally preferred due to the decreased complexity and decreased manufacturing costs.
One of the outmost critical functional elements of such check valves is their ability to seal the supply port so as to at least substantially eliminate fluid leakage therethrough. Therefore, there is a continuing need for improved self-sealing check valves.